Measuring instrument



April 1-2, 1932. J. MISCHKER I 1,853,134

MEASURING INSTRUMENT Filed Jan. 27, 1930 III III III I I III III III III II II 254 ATTORNEYS Patented Apr. 12,I 1932 1 JOHN MISGHKER, OF MILWAUKEE'WISCONSIN MEASURING INSTRUMENT App1ication filed January 27, 1930. Serial No. 423,780.

This invention relates to measuring instru-' ments and aims to provide an improved micrometer embodying an adjustable gaugemember operatively interchangeable and reversiblein a set of caliper-framesof difierent sizes for the dual purpose of makingone and the same applicable to a widely varied range of measurement and enabling ,bothinslde and outside measurements to be taken with any complete unit. e c or V The invention will be best understood by description Witlrreference to the appended drawings" illustrating one practical embodrment thereof in a conventional type of micrometer,

' In said drawings: v a

Fig. 1 is a side elevatlonof the nstrument partly in section with the gauge-memher in position for taking outside measure- 9 ments; 7

Fig. 2 is a front elevation thereof;

c F ig. 3 is a side elevation of the mstrument with the'gauge-member in position for takmg inside measurements; and g F ige is an end 'ew look ng in thedirection of thearrows in Fig. 3.

j In the illustrative instrument, a caliperframe isprovided by a conventional U-shaped body 5 of forged steel having strength and rigidity. This represents one of a set of several, of the diiferent standard sizes it being understoodthat the number of such provided are all alike except as to spanor length.

In one arm or end, this frame or body is adapted to receive an anvil-piece 6 in this in- I stance extending transversely through the arm and having one end entirely flattened and its other end slightly beveled or rounded. This anvil-piece being slidably received in the arm ofvthe frame is held frictionally against axial movement by tapered screws 7 binding tensionally thereagainst. A desirable' form of screw for this purpose is one in which the head tapers to a straight shank portion which is threaded, so that the head will exert increasing bind against the anvilpiece as it is screwed into its receiving hole. In its other armor end the frame receives and holds a gauge-member fitting slidably of micrometri-c teeth in which a pawl 10 pivotment'of the spindle. This cap is shown close-c tecting the spindle threads.

' shoulder of the latter.

therein. This gauge-member comprises an 9 of .025 inch graduation in correspondence s with standard orregulation scale markings 9 applied on another side as shown. These indentations (coordinated with said scale markings as stated) in effect provide a rack ed within a recess in the arm of the aforesaid frame may engage. This pawl is held in such engagement by a strong expanding spring 11 and hasan arm 1O projecting from its recess like the trigger of a gun for releasive movement by the finger.

The aforesaid sleeve carries a spindle 12 extending through its bore in axial alinement with the aforesaid anvil-piece 6 and with one end prO ecting therefrom toward said piece for registrative meeting therewith when sufficiently extended; This spindle is rotatively slidable in'the sleeve by thread engagement with a portion of the latter, preferably at the upper end, as represented at 13. These threads are very fine or micrometric so as to advance or retract the spindle the extent of only one indentation or quarter-graduation marl: on the sleeve in a complete turn therewithin. It ishowever preferable to extend the thread engagement slightly beyond the, intended limits of spindle movement so as to avoid upsetting the threads with rotation in either direction.

On the upper or opposite end of the spindle is applied a cap orthimble 14E affixed thereto by a removable screw-key'lti and having a knurled head facilitating itsturn movely over-engaging the upper end of the sleeve which 'for such purpose is formed with an annular neck, thereby concealingand pro- The cap thus applied limits turn movement of the spindle inwardly of the sleeve by bearing upon the t is shown graduated to .001 inch scale so thatone complete turn thereof with the spindle will be equal to .025 or an inch'or only one indentation or and reversed in the frame as shown in Fig. 3, thereby adapting it to the taking of the inside measurements with equal accuracy. In such reversal, the indented or rack side of the sleeve is again presented tot-he pawl. In the first arrangement, tl1e inside edge 5 of the frame is t'al'ren as the Zero line, and in the second arrangement the outside edge 5" there of is taken as the zero line.

It will be appreciated that this form and arrangement of tool enables a very quick adjustment to be made for the taking of any desired measurements, either inside or outside, within the range of a set oi caliper frames, since the gauge-member is int-erchangeahly and reversibly usable in any frame of the set and only one of such is therefore required for each set. This makes possible a substantial reduction in the cost of the ordinary micrometer set, where each of the frames carries and requires its own gaugemember pern'ianently aiiixed thereto. Apart from the greater convenience and lesser cost, the bulk and weight of a set is much reduced and uniformity of measurement is assured. The novelty and importance of the invention in providing such a desirable and important form of toolwill be apparent.

As thereheforevario-us forms of instruments with modifications and changes in the relation and assembly of the parts may obviously be made within the scope of the invention, it will be understood that the appended claims are not intended to limit the same to the specific form and construction shown. r

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is 1. In a micrometer, an adjustable gangemember interchangeably applicable to and reversible in caliper frames of different sizes for taking both inside and outside measurements of objects of Widely diversified proportions; said gauge-member comprising a sleeve adapted to be slidably fitted in guide openings in the frames and having a longitudinal series of micrometrically spaced indentations with coordinated standard scale graduations on the outer side thereof providing a rack engageable by spring-pressed and trigger-released pawls on the respective frames for adjustably and releasably holding it to measuring position therein, a

spindle extending slidably through said sleeve and having thread engagement with a portion thereof by which to be rotatively advanced or retracted the extent of only one indentation or quarter graduation mark of the sleeve in a complete turn, and a cap on one end of said spindle for turning the same in'the sleeve and having graduations thereon' subordinate to the graduations of the sleeve for determining fractional extents of spindle movement in opposite directions.

2'. In a micrometer, a gauge-member adapted to be removably and reversibly fitted to caliper frames of different size; said member comprising a sleeve slidably received in the frames; and having a series of closely arranged indentations in one side related to standard scale graduations thereon and pro"- viding a rack engageable by spring-pressed pawls on'the frames for holding it releasably t'ofset position therein, a spindle extending slidably through said sleeve and having thread engagement with a portion thereof by which it may be rotatively advanced or retracted the extent of only one indentation or quarter-graduation on the sleeve in a completeturn, and a cap on one" end of said spindlefor turning the same in the sleeve; said cap being graduated subordinately' to the graduations of the sleeve and limiting the turn-movement of the spindle inwardly thereof. V

3; In a micrometer, a caliper frame having an anvil-piece reversibly adjustable in one end and a slide-way opening with adjacent spring-pressed pawl in' the other, and a gauge-member slidably fitted reversibly in said opening axial alin'ement with the anvil-piece; said member comprising' a sleeve having a' longitudinal series of closely spaced indentations corresponding to standard m'icrometric scale markings on its outer side providing a rack engageahle by said pawl on the frame for"releasably'holding it to set pos'ti'on's therein, a spindle extending through and threadably engaged with said sleeve for axial movement therein with rotation in opposite directionsand a graduated cap for actuating said spindle in the sleeve; a single rotation of the spindle advancing or retarding'the same the extent of only one of the indentations on' th'eslee've.

a. In a mirrometer, a gauge-member adapted to be reversibly and interchangeably fitted in'caliper frames ofdifierent si'z'es; said member comprising a sleeve slid ably receivable in the frames and having a longitudinal series of micmmetrically spaced indentations in one side corresponding to standard scale graduations on another and providing ,a rfa ck engageableby spring-pressed pa'IWIs on the respective frames for releas'ahly holding it-tose't measuring positions therein, a' spindle extending slidably through said sleeve and having thread engagement with a portion thereof by which to be rotatably advanced or retarded the extent of only one indentation or scale mark on the sleeve in one complete turn, and a cap on one end of said spindle for turning the same in the sleeve and having graduations thereon subordinate to the graduations of the sleeve for determining fractional extents of spindle movement in opposite directions; together, with a caliper frame having an anvil-piece reversible in one end and means in'the other for receiving the gauge-member in axial alinement therewith.

5. A micrometer comprising a caliper frame having an anvil-piece in one end and an adjustable gauge-member held by a releasable spring-pressed pawl in the other end; said anvil-piece and said gauge-member both being reversibly and slidably adjustable in said frame, and said gauge-member embodyinga non-rotative sleeve having a scaled longitudinal rack-portion formed by indentations spaced at micrometric distances apart thereon and engageable by said pawl on the frame, a spindle extending through said sleeve with a portion in threaded engagement therewith for limited projective and retractive movement by screw-action, and a headcap on one end of the spindle for turning the same; said cap being extended over a portion of the sleeve and graduated with respect to a zero marking thereon for indicating fractional extents of spindle movement within the spacing distance between the indentations on said sleeve.

6. In a micrometer, an adjustable gaugemember removable from and reversible in a caliper frame for interchangeable application to frames of different sizes and for taking both inside and outside measurements of objects of widely difierent proportions; said member comprising a sleeve adapted to' be non-rotatably fitted in one end of a frame and having thereon a scaled longitudinal rackportion provided by indentations spaced at micrometric distances apart and engageable by a releasible springepressed pawl on the frame, a spindle extending through said sleeve with a portion in threaded engagement therewith for projective and retractive movement by screw action, and ahead cap on one end of the spindle for turning the same; said cap being engaged over a portion of the sleeve in opposition to a shoulder. thereon limiting the turning movement in one direction and graduated with respect to a zero marking .on

the sleeve for indicating fractional extents of spindle movement therewithin between limits of the spacing between the indentations on the sleeve.

7. In a micrometer, an adjustable gaugemember removable from and reversible in a caliper frame for interchangeable application to frames of difierent sizes and for taking both inside and outsidemeasurements of obmember comprising a sleeve adapted to be" non-rotatably fitted in oneend of a frame and having thereon a'scaled longitudinal rack portion provided by indentations spacedat micrometric distances apart and engageable by a releasable spring-pressed pawl on the frame, a spindle extending through said sleeve with a portion in threaded engagement therewith for limited screw-action projecting and retracting the same the extentof only one spacing between the indentations on the sleeve in a single complete turn, and a head cap on one end of the spindle for turning the same; said cap being engaged over a portion of'the sleeve in opposition to a shoulder thereon" jects of widely different proportions; said, I 

